CPT® Code 83505

Hydroxyproline is classified as a non-protein amino acid that is predominantly found in collagen, a vital protein that provides structure and strength to various tissues in the body, including skin, bones, and cartilage. The measurement of hydroxyproline levels can be significant in diagnosing and monitoring certain medical conditions. Elevated levels of hydroxyproline may indicate pathological conditions such as Paget's disease, which is characterized by abnormal bone remodeling, bone metastatic cancer, where cancer spreads to the bones, hyperparathyroidism, a condition that affects calcium levels in the body, osteoporosis, a disease that weakens bones, or glucocorticoid excess, which can affect various metabolic processes. Although hydroxyproline testing can serve as a non-specific marker for bone resorption, it is important to note that newer and more specific tests are now available. The accuracy of hydroxyproline test results can be influenced by dietary factors, particularly the ingestion of collagen, which may lead to elevated levels. For the CPT® Code 83505, the focus is on evaluating total hydroxyproline in urine. To ensure accurate results, patients are advised to adhere to a collagen-free diet for at least 72 hours prior to urine collection. The testing process involves collecting a 24-hour urine specimen, which is then analyzed using ion exchange chromatography or high-performance liquid chromatography (HPLC) to quantify the total hydroxyproline levels present in the urine.